Chemical Analysis - Paper 2

Question 1

What is a pure substance?

Answer 1

A single element or compound, not mixed with any other substance

Question 2

What is a characteristic of pure substances?

Answer 2

They melt and boil at specific temperatures.

So, this melting and boiling points data can be used to distinguish pure
substances from mixtures

Question 3

What is a formulation?

Answer 3

Mixture that has been designed as a useful product

Question 4

How are formulations made?

Answer 4

By mixing the components in carefully measure quantities to ensure that the products has the required properties.

Question 5

Give 3 examples of formulations?

Answer 5

Fuel
Paint
Medicine

Question 6

What is the technique of chromatography used for?

Answer 6

Used to separate mixtures and give information to help identify substances

Question 7

What does chromatography involce?

Answer 7

A stationary phase
A mobile phase

Question 8

What is the Rf value?

Answer 8

(The distance moved by substance) / ( Distance moved by solvent)

Question 9

What occurs the more soluble a substance is?

Answer 9

The more soluble a substance is, the further up the chromatography paper it travels.

Question 10

What does chromatography do?

Answer 10

Separate different pigments in a coloured substance

Question 11

What is the test for hydrogen?

Answer 11

Squeaky pop test

Question 12

Describe the squeaky pop test

Answer 12

Use a burning splint held at the open end of a test tube of the gas.

It will create a squeaky pop sound and the hydrogen burns rapidly

Question 13

What is the test for oxygen?

Answer 13

Re-lighting splint

Question 14

Describe the test for oxygen?

Answer 14

Use a glowing splint and insert into a test tube of the gas.

The splint relights in the oxygen.

Question 15

What is the test for carbon dioxide?

Answer 15

Lime water turns cloudy test

Question 16

Describe the test for carbon dioxide

Answer 16

Bubble the CO2 gas into the limewater, and it will turn cloudy

Question 17

What is the test for chlorine?

Answer 17

Litmus paper test

Question 18

Describe the test for chlorine

Answer 18

Use a damp litmus paper, and when it is put into chlorine gas, the litmus paper is bleached and will turn white.

Question 19

What is the flame test for lithium

Answer 19

Crimson

Question 20

What is the flame test for sodium?

Answer 20

Yellow

Question 21

What is the flame test for potassium?

Answer 21

Lilac

Question 22

What is the flame test for calcium?

Answer 22

Orange red

Question 23

What is the test for copper?

Answer 23

Green

Question 24

What do aluminium, calcium and magnesium ions produce with NaOH?

Answer 24

A white precipitate

Question 25

With what elements does NaOH produce a white precipitate with?

Answer 25

Aluminium Magnesum Calcium

Question 26

What happens when excess NaOH is added?

Answer 26

Aluminium precipitate dissolves.

Question 27

What does copper (II) and NaOH produce?

Answer 27

Blue precipitate

Question 28

What does Iron (II) and NaOH produce?

Answer 28

Green precipitate

Question 29

What does iron (III) and NaOH produce?

Answer 29

Brown precipitate

Question 30

What does carbonate and dilute acid produce?

Answer 30

CO2

Question 31

Chlorine + dilute nitric acid + silver nitrate =

Answer 31

White precipitate

Question 32

Bromine+ dilute nitric acid + silver nitrate =

Answer 32

Cream precipitate

Question 33

Iodine + dilute nitric acid + silver nitrate =

Answer 33

Yellow precipitate

Question 34

Sulfate + hydrochloric acid + barium chloride =

Answer 34

white precipitate

Question 35

How can elements and compounds be detected?

Answer 35

Using instrumental methods

Question 36

Advantages of instrumental methods?

Answer 36

Accurate Sensitive Rapid

Question 37

Example of instrumental test?

Answer 37

Flame emission spectroscopy

Question 38

What is the flame emission spectroscopy used for?

Answer 38

To analyse metal ions in solutions

Question 39

How does the flame emission spectroscopy work?

Answer 39

1. Sample is put into a flame and the light given out is passed through a spectroscope. 2. The output is a line spectrum, that can be analysed to identify the metal ions in the solution and measure their concentrations.